Cylindrical steel shell battery cover plate structure, battery and preparation method

Abstract

The invention relates to a cylindrical steel shell battery cover plate structure, a battery and a preparation method. The cylindrical steel shell battery cover plate structure comprises a cover plate body, a copper pole, an aluminum pole, a reinforced sealing elastic ring, a pressure relief safety valve and a pressure relief valve protection sheet, the copper pole is fixed in the central through hole of the cover plate body through the PP rubber ring to realize sealing insulation; the aluminum pole is arranged above the copper pole, and a reinforced sealing elastic ring is arranged between the aluminum pole and the copper pole; the aluminum pole enables the elastic ring to deform through pressurization and is fixed with the copper pole through laser welding or riveting, so that the elastic ring forms a sealing surface under the prestressing force; the pressure relief safety valve is connected with the aluminum pole; the protection sheet is attached to the valve; according to the structure, the sealing reliability and safety are improved through the multi-layer sealing design. The invention provides a cylindrical steel shell battery cover plate structure, a battery and a preparation method, and aims to improve the sealing reliability and safety of the battery through a multi-combination sealing design.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery, in particular to a cover plate structure of cylindrical steel shell lithium ion battery, a battery comprising the cover plate structure and a preparation method of the cover plate structure. BACKGROUND

[0002] Cylindrical steel shell lithium battery is widely used due to its high standardization degree, mature process and good structural strength. After the battery cell is loaded into the steel shell, it needs to be sealed by a cover plate structure and the positive and negative electrodes are led out. In the current mainstream cover plate structure, the connection and sealing between the core component, the nickel-plated copper pole, and the aluminum cover plate body are generally achieved by a PP glue (commonly known as "tab ear glue" in the industry) through a hot melt composite process. This process requires the PP glue to firmly bond the pole and the cover plate while ensuring electrical insulation between them.

[0003] However, in actual application, especially under complex working conditions such as long-term vibration, electrolyte immersion, high-low temperature cycling, etc., the single PP glue melting sealing structure faces challenges. Under the above stress, the PP glue material may gradually age, creep or embrittle, leading to a decrease in its sealing performance and bonding strength, and further causing risks such as battery leakage, insulation failure, etc., affecting the reliability and service life of the battery.

[0004] Therefore, the industry needs a cylindrical battery cover plate structure with higher sealing reliability, longer service life and better adaptability to complex application environments. SUMMARY

[0005] Therefore, the present application provides a cylindrical steel shell battery cover plate structure, a battery and a preparation method, which aims to improve the sealing reliability and safety of the battery through a multi-combination sealing design.

[0006] The purpose of the present application is achieved by the following technical solutions: A cylindrical steel shell battery cover plate structure, comprising: a cover plate body, a copper pole, an aluminum pole, a reinforced sealing elastic ring, a pressure relief safety valve, and a pressure relief valve protection sheet, the cover plate body has a center through hole, the copper pole is fixed in the center through hole of the cover plate body by a PP glue ring through a melting composite process, the PP glue ring realizes the sealing and insulation between the copper pole and the cover plate body; the aluminum pole is arranged on the side of the copper pole away from the battery cell, the reinforced sealing elastic ring is arranged between the copper pole and the aluminum pole, the pressure relief safety valve is connected with the aluminum pole, and the pressure relief valve protection sheet is attached to the side of the pressure relief safety valve away from the battery cell; wherein the aluminum pole applies pressure to the reinforced sealing elastic ring to make it elastically deform, and is fixedly connected with the copper pole through a laser welding or riveting process, so that the reinforced sealing elastic ring forms a sealing surface under pre-stress.

[0007] The core advantage is to build a multi-level, multi-mechanism synergistic composite sealing system, which significantly improves the long-term reliability and safety of the battery. First, through the melting composite process of the PP ring, the first sealing and insulation barrier is formed between the copper pole and the cover body, which can effectively block the direct corrosion of the electrolyte to the metal joint and ensure the electrical insulation reliability between the pole and the shell. Second, the "reinforced sealing elastic ring" and the aluminum pole are innovatively introduced, which is fixed by applying pressure and using laser welding or riveting, so that the elastic ring deforms elastically under the action of continuous prestress, thereby forming a very tight mechanical sealing interface between the copper pole and the aluminum pole. This sealing as the second line of defense, its effectiveness does not depend on the adhesive properties of the glue, so it can well overcome the inherent defects of traditional single PP glue structure in long-term vibration, electrolyte immersion and high-low temperature cycle conditions. The two sealing mechanisms complement each other, the first sealing provides basic chemical stability and insulation, and the second mechanical sealing provides persistent and stable physical compression sealing, greatly reducing the risk of battery leakage due to sealing failure at the pole. In addition, the structure integrates the pressure relief safety valve and its protective sheet, providing a controllable pressure relief channel for the battery under abnormal conditions, further enhancing the safety protection level of the battery. This modular integrated design not only improves product performance, but also gives the cover structure higher functionality and environmental adaptability.

[0008] Preferably, the sealing surface of the reinforced sealing elastic ring is provided with a first circular arc protrusion towards the cover body, or a second circular arc protrusion towards the aluminum pole, or both the first circular arc protrusion towards the cover body and the second circular arc protrusion towards the aluminum pole.

[0009] The circular arc protrusion structure provided on the sealing surface, whether it is a single first circular arc protrusion or a second circular arc protrusion, or both, has the core advantage of being able to achieve more efficient and reliable line contact or local surface contact sealing. When the aluminum pole applies pressure, the first circular arc protrusion or the second circular arc protrusion part will deform elastically first. This design can concentrate stress, and with relatively small pressure, it can generate enough contact pressure, thereby quickly forming an effective sealing line. This contact method helps to overcome the leakage path that may exist due to the microscopic unevenness of the sealing contact surface, improving the immediacy and consistency of the seal. At the same time, the circular arc protrusion design has better stress distribution characteristics than purely flat or sharp designs, reducing the risk of plastic deformation or stress cracking under long-term pressure, helping to maintain the long-term stability of the pre-stress, thereby prolonging the sealing life. Providing first circular arc protrusion, second circular arc protrusion or double-sided and other optional schemes also increases the flexibility of the design, making it able to adapt to battery designs with different internal space structures and assembly process requirements, expanding the application range of the technology.

[0010] Preferably, the outer diameter of the reinforced sealing elastic ring is designed with a taper.

[0011] The design of the outer diameter with a taper allows the sealing ring to play a good guiding and centering role during the process of being pressed into the corresponding inner hole of the cover plate body, simplifying the assembly process, facilitating the realization of automated production and improving the assembly precision and efficiency. More importantly, the taper structure can naturally form a gradual interference fit during the pressing process. As the pressing depth increases, the radial contact pressure between the larger end of the outer diameter of the sealing ring and the installation hole wall will gradually increase. This radial pressure will cause slight radial elastic deformation of the material of the sealing ring, so that its outer wall fits more tightly with the inner wall of the installation hole, which is equivalent to an additional radial auxiliary sealing barrier in addition to the axial sealing. This barrier can further prevent the electrolyte from penetrating along the path of the outer wall of the sealing ring, enhancing the redundancy and overall reliability of the seal. The taper design allows the sealing ring to have a self-tightening effect when subjected to internal pressure, helping to improve its sealing retention capability under complex working conditions.

[0012] Preferably, the size of the pressure relief port of the pressure relief safety valve is configured to be adjustable according to the required pressure relief pressure.

[0013] By designing the size of the pressure relief port of the pressure relief safety valve to be adjustable, it means that the battery's pressure relief trigger pressure can be accurately set according to the specific safety standards and performance requirements of different customers and different battery models. For example, for batteries that pursue higher energy density, it may be necessary to trigger pressure relief slightly earlier to absolutely ensure safety; while for some high-power applications, a higher trigger pressure may be set. This adjustability allows manufacturers to use the same basic cover plate structure and quickly derive a product series that meets various technical specifications by changing the design of the pressure relief port, significantly reducing mold development costs and production management complexity. At the same time, this also enables the battery to better adapt to possible future updates in safety regulations and test standards, improving the forward-looking and life cycle of the product technology roadmap.

[0014] Preferably, the cover plate body is made of aluminum alloy or SUS304 material.

[0015] The aluminum alloy is used as the cover plate body material, which has the advantages of low density, which helps to reduce the overall weight of the battery, which is particularly important for portable electronic devices. At the same time, the aluminum alloy has good thermal conductivity, which is conducive to the faster dissipation of heat generated by the battery during charging and discharging through the cover plate, which has a positive impact on thermal management. In addition, the aluminum alloy has excellent processability and relatively low cost. SUS304 stainless steel is used as another option, which has the core advantages of high mechanical strength and excellent corrosion resistance. SUS304 material can better withstand the thermal stress and mechanical stress generated when laser welding is used between the cover plate and the steel shell, ensuring the firmness and sealing integrity of the welded joint. It also has stronger corrosion resistance to electrolyte, especially suitable for more demanding application environments or situations with extremely high long-term reliability requirements. Providing these two material options gives battery manufacturers the flexibility to choose according to their process route (spin riveting or laser welding) and product positioning (cost or performance).

[0016] Preferably, a cylindrical steel shell battery includes a steel shell, a cell, and a cover plate, the cover plate being a cylindrical steel shell battery cover plate structure as described above; a sealing ring is arranged between the cover plate and the steel shell; the cover plate and the steel shell are sealed and connected by a spin riveting process, wherein the spin riveting position of the steel shell produces plastic deformation, the plastic deformation force is transmitted to the sealing ring to make it elastically deformed, forming a sealing surface.

[0017] The core advantage is to achieve multi-level sealing and process maturity of the overall battery packaging. By using the cover plate structure as described above, the sealing at the internal pole of the battery has been strengthened multiple times as described above, fundamentally reducing the risk of internal liquid leakage. On this basis, the cover plate and the steel shell are packaged by arranging a separate sealing ring and using a spin riveting process, which builds another independent external sealing barrier. The spin riveting process is a very mature, reliable and cost-effective mechanical connection method, which forms a durable and reliable static seal by deforming the steel shell opening and pressing the sealing ring, using the elastic recovery force of the sealing material. This seal mainly prevents moisture, dust and other external environmental factors from entering the battery interior, while also preventing battery interior gases from escaping. The internal pole seal and the external shell seal are independent of each other and complement each other, together forming an extremely reliable battery packaging system, which significantly improves the sealing integrity and long-term reliability of the battery in various application environments.

[0018] Preferably, when the spin riveting process is used, the spin riveting position of the steel shell produces plastic deformation, the plastic deformation force is transmitted to the sealing ring to make it elastically deformed, forming a sealing surface.

[0019] The advantage is that the transmission path of the sealing force and the essence of the sealing formation are clear, and the reliability and adaptability of the sealing method are highlighted. The feature emphasizes that the formation of the seal is not dependent on additional fasteners or adhesives, but cleverly uses the plastic deformation of the steel shell body material as a power source. The force applied by the spin riveting tool causes permanent deformation of the steel shell mouth. This deformation process continuously compresses the elastic sealing ring between the cover plate and the steel shell. The sealing ring deforms elastically after being compressed, and its elastic force uniformly acts on the contact surface of the cover plate and the steel shell, filling all microscopic irregularities, thereby forming a continuous and stable sealing interface. This sealing method has a certain fault tolerance to part processing precision and assembly errors. As long as sufficient compression is ensured, effective sealing can be achieved, which reflects good process robustness. The sealing based on elastomer deformation also has a certain compensation effect, which can maintain effective sealing state when the pre-pressure is slightly relaxed due to vibration or temperature change in long-term use.

[0020] Preferably, a cylindrical steel shell battery includes a steel shell, a cell, and a cover plate, the cover plate is a cylindrical steel shell battery cover plate structure as described above; the cover plate and the steel shell are sealed and connected by a laser welding process, and the welding surface of the cover plate and the steel shell forms a seal.

[0021] This is another solution for battery packaging, which has the advantages of realizing a battery package with higher strength, higher sealing level, and better space utilization. The laser welding process is used instead of the traditional mechanical spin riveting to form a metallurgical bonded weld at the connection between the cover plate and the steel shell. The strength of this weld is usually much higher than that of the base material itself, making the overall structure of the battery more rigid and able to withstand higher internal pressure and more intense external mechanical impact and vibration, significantly improving the mechanical safety performance of the battery. The seal formed by laser welding is a dense metal seal, which is theoretically superior to the mechanical seal relying on elastomer deformation in terms of air and liquid tightness, and can almost completely block the exchange of internal and external substances, especially suitable for extremely demanding applications. In addition, laser welding is a non-contact, high-precision processing method with small heat-affected zone and small deformation, which helps to maintain the appearance quality and dimensional accuracy of the battery. At the same time, the space for the flanging structure required by the spin riveting process is saved, which is conducive to improving the volumetric energy density of the battery.

[0022] Preferably, a method for manufacturing a cylindrical steel shell battery cover plate structure as described above, comprising the following steps: S1: using a PP glue ring to compound and form a first assembly by a melt compounding process, the PP glue ring achieving sealing and insulation; S2: placing a reinforced sealing elastic ring on the copper pole of the first assembly; S3: assembling an aluminum pole in place and applying pressure to it, so that the reinforced sealing elastic ring is elastically deformed under stress; S4: using a laser welding or riveting process to fixedly connect the copper pole and the aluminum pole, forming a second assembly; S5: welding a pressure relief safety valve to the aluminum pole of the second assembly, forming a third assembly; S6: bonding a pressure relief valve protection sheet to the third assembly to form a complete battery cover plate.

[0023] The method has the advantages of clear process, strong operability, and high performance and consistency of the product. The method adopts a step-by-step assembly and integration strategy to decompose the complex multilayer structure into multiple simple processes, which is beneficial to realize automatic production and precise quality control. Step S1 first solves the basic electrical insulation and the first sealing problem by a mature melt compounding process, providing a reliable installation foundation for subsequent assemblies. Steps S2 to S4 are the key to forming the core mechanical seal: first place the elastic ring, then pre-achieve the design deformation state by applying pressure, and finally permanently lock this state by laser welding or riveting. This sequence ensures that the sealing ring can always be in the best pre-stressed state, thereby ensuring the uniformity and stability of the sealing performance of the final product. The selection of laser welding or riveting process provides flexibility and forms a high-strength and reliable mechanical connection. Subsequent steps S5 and S6 integrate the safety function modules to complete the assembly of the final product. The entire method has a logical process, and each step lays a foundation for the next step, ultimately ensuring the realization of the excellent performance of the cover plate structure.

[0024] Preferably, in step S5, the size of the pressure relief port of the pressure relief safety valve is determined according to the material yield strength and the target pressure relief pressure.

[0025] The design of the safety-critical pressure relief valve is directly linked to material science and engineering goals, emphasizing a scientifically-based, precise design approach rather than relying on experience or trial-and-error. The core function of the pressure relief valve is to actuate at a specific pressure, and the trigger pressure is mainly determined by the structure of the valve body (especially the size of the thinnest relief port) and the mechanical properties of the material (such as yield strength). This method clearly requires the precise size of the relief port to be determined by back-calculation based on the actual yield strength of the selected material and the target relief pressure required by the product design. This physically-based design approach can significantly improve the consistency, accuracy and reliability of the relief valve's action pressure, reducing performance fluctuations due to manufacturing tolerances or material batch differences. It ensures that each batch of pressure relief valves can be precisely opened within the preset safety threshold, greatly improving the reliability and consistency of the battery safety protection function, meeting the stringent requirements of the high-end application market for battery safety performance.

[0026] The beneficial effects of the present application compared to the prior art are: 1. Multiple composite seals, improved reliability: The cover plate structure of the present application adopts at least two core sealing mechanisms. The first is the fusion composite seal provided by the PP rubber ring, mainly responsible for insulation and initial sealing. The second is the mechanical seal composed of a pre-pressed reinforced sealing elastic ring. The two seals work together and back up each other, so even if the PP glue performance decreases due to long-term aging, the mechanical seal can still play an effective role, thereby significantly reducing the risk of battery leakage and improving the long-term reliability of the battery in harsh working conditions.

[0027] 2. Material and process selection is flexible: The cover plate body can be made of aluminum alloy or stainless steel (such as SUS304), etc., allowing the cover plate to adapt to both spin riveting and laser welding shell sealing processes. This provides battery manufacturers with more design flexibility and process selection space, allowing them to choose the optimal solution based on product positioning and line configuration.

[0028] 3. Enhanced safety: The integrated safety valve structure with a designed relief pressure provides important safety protection for the battery. The size of the relief port can be adjusted according to the material strength and target pressure to meet different safety standard requirements.

[0029] 4. Optimized structure design: The design of the arc protrusion and taper on the reinforced sealing elastic ring helps form more effective linear or surface seals during assembly, improves stress distribution, and makes the assembly process smoother, which is beneficial to improving production yield and consistency. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0031] Figure 1 The structural diagram of the cylindrical steel shell battery cover plate structure of the embodiment 1 of the present application.

[0032] Figure 2 The structural diagram of the cylindrical steel shell battery cover plate structure of the embodiment 2 of the present application.

[0033] Figure 3 The structural diagram of the cylindrical steel shell battery cover plate structure of the embodiment 3 of the present application.

[0034] Label explanation: 1 cover plate body, 2 copper pole, 3 PP rubber ring, 4 aluminum pole, 5 reinforced sealing elastic ring, 51 first circular arc protrusion, 52 second circular arc protrusion, 6 pressure relief safety valve, 61 pressure relief port, 7 pressure relief valve protection sheet. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0037] It should be noted that similar reference numerals and letters refer to like items in the accompanying drawings, and once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings. In the description of embodiments of the present application, it should be understood that the terms "upper", "lower", "left", "right", "vertical", "horizontal", and the like, are words of convenience and are not to be construed as limiting terms unless otherwise indicated by the context. These terms merely identify the orientation in use or application and the position of one part or element relative to another in the drawings and use of these terms is by no means intended to limit the position to which an element can be placed in an actual device in use or application. Therefore, description herein using terms such as "upper" or "lower" does not limit the position of an element to a particular orientation in use or application, but rather the orientation is used in the description for convenience.

[0038] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0039] The technical solutions in the present application will be described below in conjunction with the accompanying drawings. Embodiment 1

[0040] The present embodiment provides a cylindrical steel shell battery cover plate structure, comprising: a cover plate body 1 with a center through hole; a copper pole 2 fixed in the center through hole of the cover plate body 1 by a PP rubber ring 3 through a fusion composite process, the PP rubber ring 3 realizing the sealing and insulation between the copper pole 2 and the cover plate body 1; an aluminum pole 4 arranged on the side of the copper pole 2 away from the battery cell; a reinforced sealing elastic ring 5 arranged between the copper pole 2 and the aluminum pole 4; a pressure relief safety valve 6 connected with the aluminum pole 4; and a pressure relief valve protection sheet 7 attached to the side of the pressure relief safety valve 6 away from the battery cell; wherein the aluminum pole 4 applies pressure to the reinforced sealing elastic ring 5 to make it elastically deform, and is fixedly connected with the copper pole 2 through a laser welding or riveting process, so that the reinforced sealing elastic ring 5 forms a sealing surface under prestress.

[0041] The core advantage is to build a multi-level, multi-mechanism synergistic composite sealing system, which significantly improves the long-term reliability and safety of the battery. First, through the melting composite process of the PP ring 3, a first sealing and insulation barrier is formed between the copper pole 2 and the cover body 1, which can effectively block the direct corrosion of the electrolyte to the metal joint, and ensure the electrical insulation reliability between the pole and the shell. Second, the "reinforced sealing elastic ring 5" and the aluminum pole 4 cooperating with it are innovatively introduced, and the elastic ring is deformed under the action of continuous prestress by applying pressure and fixed by laser welding or riveting, so that a very tight mechanical sealing interface is formed between the copper pole 2 and the aluminum pole 4. This sealing as the second line of defense, its effectiveness does not depend on the adhesive properties of the glue, so it can well overcome the inherent defects of traditional single PP glue structure in long-term vibration, electrolyte immersion and high-low temperature cycle conditions. The two sealing mechanisms complement each other, the first sealing provides basic chemical stability and insulation, and the second mechanical sealing provides persistent and stable physical compression sealing, greatly reducing the risk of battery leakage due to sealing failure at the pole. In addition, the structure integrates the pressure relief safety valve 6 and its protective sheet 7, providing a controllable pressure relief channel for the battery in abnormal conditions, further enhancing the safety protection level of the battery. This modular integrated design not only improves product performance, but also gives the cover structure higher functionality and environmental adaptability.

[0042] The PP ring 3 is made of polypropylene (PP) material, or modified with polypropylene as the base. The selection of this material is based on its high adaptability to the application environment of lithium ion batteries: first, polypropylene has excellent corrosion resistance and low swelling rate to the common organic electrolyte (such as carbonate solvents) inside the battery, which can maintain dimensional stability and sealing integrity for a long time, avoiding sealing failure due to material degradation; second, polypropylene has good electrical insulation performance, which can reliably ensure the electrical isolation between the copper pole 2 and the cover body 1 made of aluminum alloy or stainless steel, preventing short circuit; finally, as a thermoplastic material, polypropylene can form a dense and firm fusion interface with metal parts (copper pole and cover body) through melting composite process under specific temperature and pressure, realizing integrated molding of structural bonding and sealing. Therefore, the PP ring 3 is not an ordinary sealing ring, but a key component that integrates insulation, structural bonding and primary sealing functions. The material properties of the PP ring 3 are the basis for the mechanical sealing of the reinforced sealing elastic ring 5 to work effectively.

[0043] In this embodiment, the sealing surface of the reinforced sealing elastic ring 5 is provided with a first circular arc protrusion 51 facing the cover body 1 and a second circular arc protrusion 52 facing the aluminum pole 4.

[0044] The arc convex structure arranged on the sealing surface has the core advantages of realizing more efficient and more reliable line contact or local surface contact sealing. When the aluminum pole 4 applies pressure, the first arc convex 51 or the second arc convex 52 part will preferentially undergo elastic deformation. This design can concentrate stress, and a relatively small pressure contact force can generate a large enough contact pressure, thereby quickly forming an effective sealing line. This contact mode helps to overcome the leakage path that may exist due to the micro-unevenness of the sealing contact surface, and improves the immediacy and consistency of the sealing. At the same time, the arc convex design has better stress distribution characteristics than the purely flat or sharp corner design, reduces the risk of plastic deformation or stress cracking under long-term pressure, helps to maintain the long-term stability of the pre-pressure, and thus prolongs the sealing life.

[0045] In the embodiment, the outer diameter of the reinforced sealing elastic ring 5 is provided with a taper.

[0046] The tapered outer diameter design enables the sealing ring to play a good guiding and centering role during the process of being pressed into the corresponding inner hole of the cover plate body 1, simplifies the assembly process, is conducive to realizing automatic production and improving assembly precision and efficiency. More importantly, the taper structure can naturally form a gradual interference fit during the pressing process. As the pressing depth increases, the radial contact pressure between the larger end of the outer diameter of the sealing ring and the installation hole wall will gradually increase. This radial pressure will cause slight radial elastic deformation of the material of the sealing ring, so that the outer wall of the sealing ring is more tightly fitted with the inner wall of the installation hole, which is equivalent to additionally increasing a radial auxiliary sealing barrier in addition to the axial sealing. This barrier can further prevent the electrolyte from penetrating along the circumferential path of the outer wall of the sealing ring, and enhance the redundancy and overall reliability of the sealing. The taper design enables the sealing ring to have a self-tightening effect when bearing internal pressure, which helps to improve its sealing retention capability under complex working conditions.

[0047] In the embodiment, the pressure relief port 61 of the pressure relief safety valve 6 is configured to be adjustable according to the required pressure relief pressure.

[0048] By designing the pressure relief port 61 of the pressure relief safety valve 6 to be configurable in size, it means that the battery's pressure relief trigger pressure can be precisely set according to different customers, different battery models, and specific safety standards and performance requirements. For example, for batteries that pursue higher energy density, it may be necessary to trigger pressure relief slightly earlier to absolutely ensure safety; while for some high-power applications, a higher trigger pressure may be set. This adjustability allows manufacturers to use the same basic cover plate structure 1, by changing the design of the pressure relief port 61, to quickly derive a product series that meets various technical specifications, significantly reducing mold development costs and production management complexity. At the same time, it also makes the battery better adapt to possible future updates to safety regulations and test standards, improving the forward-looking and life cycle of the product technology roadmap.

[0049] In this embodiment, the cover plate body 1 is made of aluminum alloy or SUS304 material.

[0050] Using aluminum alloy as the material for the cover plate body 1 has the advantage of lower density, which helps to reduce the overall weight of the battery, which is particularly important for portable electronic devices. At the same time, aluminum alloy has good thermal conductivity, which is beneficial for the heat generated during charging and discharging to be dissipated more quickly through the cover plate, having a positive impact on thermal management. In addition, aluminum alloy has excellent processing performance and relatively low cost. Using SUS304 stainless steel as an alternative has the core advantage of extremely high mechanical strength and excellent corrosion resistance. SUS304 material can better withstand the thermal and mechanical stresses generated during laser welding between the cover plate and the steel shell, ensuring the firmness and integrity of the welded joint. It also has stronger corrosion resistance to electrolyte, especially suitable for more demanding application environments or situations where long-term reliability is extremely important. Providing these two material options gives battery manufacturers the flexibility to choose according to their process route (spin riveting or laser welding) and product positioning (cost or performance). Embodiment 2

[0051] In this embodiment, compared to Embodiment 1, the sealing surface of the reinforced sealing elastic ring 5 is provided with a first circular arc protrusion 51 facing the cover plate body 1.

[0052] The arc convex structure arranged on the sealing surface has the core advantages of realizing more efficient and more reliable line contact or local surface contact sealing. When the aluminum pole column 4 applies pressure, the first arc convex 51 will preferentially elastically deform, and this design can concentrate stress, and a relatively small pressure contact force can generate a large enough contact pressure, thereby quickly forming an effective sealing line. This contact mode helps to overcome the leakage path that may exist due to the micro-unevenness of the sealing contact surface, and improves the immediacy and consistency of the sealing. At the same time, the arc-shaped convex design has better stress distribution characteristics than the purely planar or sharp corner design, reduces the risk of plastic deformation or stress cracking under long-term pressure, helps to maintain the long-term stability of the pre-pressure, and thus prolongs the sealing life. Example 3

[0053] In this embodiment, compared with example 1, the sealing surface of the reinforced sealing elastic ring 5 is provided with a second arc convex 52 towards the aluminum pole column 4.

[0054] The arc convex structure arranged on the sealing surface has the core advantages of realizing more efficient and more reliable line contact or local surface contact sealing. When the aluminum pole column 4 applies pressure, the first arc convex 51 will preferentially elastically deform, and this design can concentrate stress, and a relatively small pressure contact force can generate a large enough contact pressure, thereby quickly forming an effective sealing line. This contact mode helps to overcome the leakage path that may exist due to the micro-unevenness of the sealing contact surface, and improves the immediacy and consistency of the sealing. At the same time, the arc-shaped convex design has better stress distribution characteristics than the purely planar or sharp corner design, reduces the risk of plastic deformation or stress cracking under long-term pressure, helps to maintain the long-term stability of the pre-pressure, and thus prolongs the sealing life. Example 4

[0055] In this embodiment, a cylindrical steel shell battery includes a steel shell, a battery cell, and a cover plate, the cover plate is a cylindrical steel shell battery cover plate structure as in example 1 or 2 or 3; a sealing ring is arranged between the cover plate and the steel shell; the cover plate and the steel shell are sealed and connected by a spin riveting process, wherein the spin riveting position of the steel shell produces plastic deformation, and the plastic deformation force is transmitted to the sealing ring to make it elastically deform, forming a sealing surface.

[0056] The core advantage is to realize the multi-level sealing of the overall battery package and the process maturity. By using the cover plate structure 1, the sealing at the internal pole of the battery has been reinforced multiple times as described above, fundamentally reducing the risk of internal liquid leakage. On this basis, the cover plate and the steel shell are sealed by setting a separate sealing ring and using a spin riveting process to build another independent external sealing barrier. The spin riveting process is a very mature, reliable and cost-effective mechanical connection method. By plastically deforming the steel shell opening and compressing the sealing ring, a durable and reliable static seal is formed using the elastic restoring force of the sealing material. This sealing main The purpose is to prevent moisture, dust and other external environmental factors from entering the battery interior, while also preventing the battery interior gas from escaping. The internal pole sealing and the external shell sealing are independent of each other and complement each other, together forming an extremely reliable battery packaging system, greatly improving the sealing integrity and long-term reliability of the battery in various application environments.

[0057] In this embodiment, when the spin riveting process is used, the spin riveting position of the steel shell plastically deforms, and the plastic deformation force is transmitted to the sealing ring to cause elastic deformation, forming a sealing surface.

[0058] The advantage is that the transmission path of the sealing force and the nature of the sealing formation are clearly defined, highlighting the reliability and adaptability of this sealing method. This feature emphasizes that the formation of the seal does not rely on additional fasteners or adhesives, but rather cleverly uses the plastic deformation of the steel shell body material as a power source. The force applied by the spin riveting tool causes permanent deformation of the steel shell opening, which continuously compresses the elastic sealing ring located between the cover plate and the steel shell. The sealing ring elastically deforms after being compressed, and its elastic force uniformly acts on the contact surface of the cover plate and the steel shell, filling all microscopic irregularities, thereby forming a continuous and stable sealing interface. This sealing method has a certain fault tolerance to part processing precision and assembly errors. As long as sufficient compression is ensured, the seal can be effectively achieved, demonstrating good process robustness. The sealing based on elastic body deformation also has a certain compensation effect, which can maintain an effective sealing state when the pre-compression is slightly relaxed due to vibration or temperature changes over a long period of use. Embodiment 5

[0059] In this embodiment, a cylindrical steel shell battery includes a steel shell, a battery cell, and a cover plate, the cover plate being a cylindrical steel shell battery cover plate structure as in Embodiment 1 or 2 or 3; the cover plate and the steel shell are sealed and connected by a laser welding process, and the welding surface of the cover plate and the steel shell forms a seal.

[0060] This is another solution for battery packaging, which has the advantages of realizing higher strength, higher sealing level and better space utilization. Using laser welding process instead of traditional mechanical riveting, a metallurgical bonded weld can be formed at the connection between the cover plate and the steel shell. The strength of this weld is usually much higher than the base material itself, making the overall structure of the battery more rigid and able to withstand higher internal pressure and more intense external mechanical impact and vibration, significantly improving the mechanical safety performance of the battery. The seal formed by laser welding is a dense metal seal, which is theoretically superior to mechanical sealing relying on elastomer deformation in terms of air and liquid tightness, and can almost completely block the exchange of internal and external substances, especially suitable for extremely demanding applications. In addition, laser welding is a non-contact, high-precision processing method with small heat-affected zone and small deformation, which helps to maintain the appearance quality and dimensional accuracy of the battery. At the same time, the space for flanging structure that may be needed in the riveting process is saved, which is beneficial to improve the volume energy density of the battery. Example 6

[0061] In this embodiment, a method for preparing a cylindrical steel shell battery cover plate structure as in example 1 or 2 or 3, comprising the following steps: S1: composite molding of copper pole 2 and cover plate body 1 with central through hole using PP glue ring 3 by fusion composite process to form a first assembly, and PP glue ring 3 realizes sealing and insulation; S2: placing a reinforced sealing elastic ring 5 on the copper pole 2 of the first assembly; S3: assembling the aluminum pole 4 in place and applying pressure to it, so that the reinforced sealing elastic ring 5 is elastically deformed under stress; S4: using laser welding or riveting process to fixedly connect the copper pole 2 and the aluminum pole 4, forming a second assembly; S5: welding the pressure relief safety valve 6 with the aluminum pole 4 of the second assembly to form a third assembly; S6: bonding the pressure relief valve protection sheet 7 with the third assembly to form a complete battery cover plate.

[0062] The preparation method has the advantages that a clear process is defined, operability is high, and an assembly process capable of guaranteeing high performance and high consistency of products is provided. The method adopts a step-by-step assembly and step-by-step integration strategy, decomposes a complex multi-layer structure into multiple simple processes, and is beneficial to realize automatic production and precise quality control. In step S1, the mature melt composite process is used to stably solve the basic electrical insulation and the first sealing problem, and provide a reliable installation basis for subsequent components. Steps S2 to S4 are the key to forming the core mechanical seal: the elastic ring is placed first, then the elastic ring is pre-deformed by applying pressure, and finally the state is permanently locked by laser welding or riveting. This sequence ensures that the sealing ring can always be in the best pre-stressed state, thereby guaranteeing the uniformity and stability of the sealing performance of the final product. The selection of the laser welding or riveting process provides flexibility and forms a high-strength and high-reliability mechanical connection. Subsequent steps S5 and S6 integrate the safety function module to complete the assembly of the final product. The entire method process is logically rigorous, each step lays a foundation for the next step, and finally guarantees the realization of various excellent performances of the cover plate structure 1.

[0063] In this embodiment, in step S5, the size of the pressure relief port 61 of the pressure relief safety valve 6 is determined according to the material yield strength and the target pressure relief pressure.

[0064] The design of the pressure relief valve, a safety-critical component, is directly related to the material science and engineering target, emphasizing a precise design method based on scientific calculation rather than relying on experience or trial and error. The core function of the pressure relief safety valve 6 is to act in time at a specific pressure, and the trigger pressure mainly depends on the structure of the valve body (especially the size of the thinnest pressure relief port 61) and the mechanical properties of the material (such as yield strength). The method clearly requires that the accurate size of the pressure relief port 61 be back-calculated and determined according to the actual yield strength of the selected material and the target pressure relief pressure required by the product design. This design method based on physical principles can significantly improve the consistency, accuracy and reliability of the pressure relief valve action pressure, reduce the performance fluctuations caused by manufacturing tolerances or material batch differences. It ensures that each batch of produced pressure relief safety valves 6 can accurately open within the preset safety threshold, thereby greatly improving the reliability and consistency of the battery safety protection function, and meeting the stringent requirements of the high-end application market for battery safety performance.

[0065] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A cylindrical steel can battery cover plate structure, characterized by, include: Cover plate body (1) with a central through hole; The copper electrode post (2) is fixed in the central through hole of the cover plate body (1) by a PP rubber ring (3) through a melt composite process. The PP rubber ring (3) achieves sealing and insulation between the copper electrode post (2) and the cover plate body (1). An aluminum electrode post (4) is disposed on the side of the copper electrode post (2) away from the battery cell; A reinforced sealing elastic ring (5) is disposed between the copper electrode post (2) and the aluminum electrode post (4); A pressure relief safety valve (6) is connected to the aluminum pole (4); and Pressure relief valve protection plate (7), which is attached to the side of the pressure relief safety valve (6) away from the battery cell; The aluminum pole (4) is subjected to pressure on the reinforcing sealing elastic ring (5) to cause it to deform elastically, and is fixedly connected to the copper pole (2) by laser welding or riveting process, so that the reinforcing sealing elastic ring (5) forms a sealing surface under prestress.

2. The cylindrical steel can battery cover plate structure of claim 1, wherein, The sealing surface of the reinforced sealing elastic ring (5) is provided with a first arc protrusion (51) facing the cover plate body (1) or a second arc protrusion (52) facing the aluminum pole (4), or both a first arc protrusion (51) facing the cover plate body (1) and a second arc protrusion (52) facing the aluminum pole (4) are provided.

3. The cylindrical steel can battery cover plate structure according to claim 1 or 2, characterized by, The outer diameter of the reinforced sealing elastic ring (5) is tapered.

4. The cylindrical steel can battery cover plate structure of claim 1, wherein, The pressure relief port (61) of the pressure relief safety valve (6) is configured to be adjustable according to the required pressure relief.

5. The cylindrical steel can battery cover plate structure of claim 1, wherein The cover plate body (1) is made of aluminum alloy or SUS304 material.

6. A cylindrical steel can battery comprising a steel can, an electrode core and a cover plate, characterized in that, The cover plate is the cylindrical steel shell battery cover plate structure as described in any one of claims 1 to 5; A sealing ring is provided between the cover plate and the steel shell; The cover plate and the steel shell are sealed together by riveting. The riveting position of the steel shell undergoes plastic deformation, and the plastic deformation force is transmitted to the sealing ring, causing it to elastically deform and form a sealing surface.

7. The cylindrical steel can battery of claim 6 wherein, When the riveting process is used, the riveting position of the steel shell undergoes plastic deformation. The plastic deformation force is transmitted to the sealing ring, causing it to elastically deform and form a sealing surface.

8. A cylindrical steel can battery comprising a steel can, an electrode core and a cover plate, characterized in that, The cover plate is the cylindrical steel shell battery cover plate structure as described in any one of claims 1 to 5; The cover plate and the steel shell are sealed together by laser welding, and the welded surfaces of the cover plate and the steel shell form a seal.

9. A method of manufacturing the cover plate structure of the cylindrical steel shell battery according to claim 1, characterized by, Includes the following steps: S1: The copper pole post (2) and the cover plate body (1) with a central through hole are composite molded by PP rubber ring (3) through a melt composite process to form the first component. The PP rubber ring (3) achieves sealing and insulation. S2: Place a reinforcing sealing elastic ring (5) on the copper pole (2) of the first component; S3: Assemble the aluminum pole (4) into place and apply pressure to it, so that the reinforcing sealing elastic ring (5) is subjected to force and undergoes elastic deformation; S4: The copper pole (2) and the aluminum pole (4) are fixedly connected by laser welding or riveting to form a second component; S5: Weld the pressure relief safety valve (6) to the aluminum pole (4) of the second component to form the third component; S6: Bonding the pressure relief valve protection sheet (7) with the third assembly to form a complete battery cover plate.

10. The method of claim 9, wherein, In step S5, the pressure relief port size of the pressure relief safety valve (6) is determined according to the material yield strength and the target pressure relief pressure.

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